Tipping is simply not part of Singaporean culture, at restaurants, in taxis, or at hotels.
What looks like a confusing bill is usually just two separate add-ons: a 10% service charge, then GST (goods and services tax) calculated on top of that — neither is a tip, both go to the business and the government respectively.
Hawker centres, Singapore's famous food courts, never involve tipping of any kind — you pay the exact price shown and that is the end of the transaction.
Reading a Singapore restaurant bill
Menu price: S$30.00
+10% service charge: S$3.00
+9% GST (on the S$33.00 subtotal): S$2.97
Final total: S$35.97 — no tip required anywhere in that calculation.
Taxis and rideshare
Fares are metered and exact change is standard. Rounding up to the nearest dollar is sometimes done but is a rounding convenience, not a tipping gesture, and plenty of locals simply take their exact change.
If you still want to show appreciation: for genuinely exceptional, personalised service — a tour guide who went well beyond the job, for instance — a small cash gift is accepted gracefully, but it is a personal gesture rather than any kind of expected practice.
Why Singapore differs from, say, Thailand or the UAE
Singapore's service charge and GST system is set by regulation and applied consistently across almost every licensed restaurant, which is part of why the custom here is so settled compared with neighbouring countries where a service charge may or may not appear, and may or may not reach staff. There is little ambiguity to resolve with an extra tip, because the add-ons on a Singapore bill are standardised and transparent.